The present invention relates generally to image identification and, more specifically, to a computer-implemented method for analyzing, identifying, and comparing images.
With the development of computers and electronic networks such as the Internet, it is now possible to create, represent, and store, and view electronic representations of visually displayed images such as photographs, paintings, and prints. In addition to such electronic representations of xe2x80x9chard-copyxe2x80x9d images, computer generated art forms that are created, stored, and viewed exclusively as electronic representations are becoming more common.
Electronic representations, such as digital images, are extremely easy to duplicate. Unfortunately, it can be difficult or impossible to determine whether an electronic image is an original image, or is a duplicate of the original. Furthermore, the Internet has greatly facilitated the transmitting of duplicated images. This can be a significant problem for artists, copyright owners, and others who have interests in particular images.
Attempts have been made to mark electronic images to permit identification of unauthorized copies. For example, a digital watermark can be added to an electronic image. A suspected duplicate image can be identified by its hidden digital watermark. However, a digital watermark is located at one or more specific locations on an electronic image. Thus, if the portion of an image in which the watermark is stored is cropped upon duplication, image identification will not be possible using the digital watermark.
Furthermore, a digital watermark must be affirmatively added to an electronic image. Therefore, it is not possible to use this method to identify copies of images that either have not been digitally watermarked, or that were made prior to the addition of a digital watermark.
In addition, a digital watermark may not survive the transfer of an electronic image to printed format. For example, a duplicate digital image can be downloaded from the Internet and printed. The unauthorized print may not display the digital watermark.
It would be an advantage to provide a method and apparatus for identifying an image without requiring the use of an identifying mark. It would be a further advantage if such method and apparatus enabled the identification of altered duplicate images, such as cropped images. It would be yet another advantage if such method and apparatus were available to search an electronic network to locate, compare, and identify images.
The present invention is a computer-implemented method and apparatus for analyzing, identifying, and comparing images. The method can be used with any visually-displayed medium that is represented in any type of color space. An identified image can be authenticated, registered, marked, compared to another image, or recognized using the method and apparatus according to the present invention.
In the present invention, an image""s displayed composition is parsed to generate unique image characteristics. At least one characteristic of the image""s color space is selected and determined for a displayed image. In the preferred embodiment of the invention, the selected characteristics include color distribution, color space usage, color range distance, and image size. The information determined for each selected characteristic comprises a unique description of an image. This identification information can be then used to compare different identified images to determine if they are identical.
In the preferred embodiment of the present invention, a plurality of color values are combined to provide an expressed color value. In one embodiment, the color values are combined by grouping colors that cannot be distinguished by visual inspection. In an alternative embodiment, the color values are combined by truncating a specified number of the lower bits representing each color value and then by combining all color values whose remaining bits are equal in value.
A set of predetermined criteria is used to ascertain whether a second image is a duplicate of a first image. Such criteria can include the percentage of identity of the determined characteristics of the compared image. Thus, if the determined characteristics are identical within the predetermined percentage, the images will be considered to be duplicates. The predetermined criteria can be adjusted to permit the identification of images that are identical in part, such as a clipped copy of an image compared to an original.
In the preferred embodiment of the present invention, a software search application, such as a search engine or a spider, is used to retrieve an image from an electronic network. The retrieved image can then be identified using the method of the present invention. The software search application can be used to search an electronic network, such as the Internet, to seek out copies of an identified image. In one embodiment, a notification alarm is provided when a duplicate image is located.
In one embodiment, the present invention is implemented using a computer. In this embodiment, identification information for an image can be stored in a computer-accessible database. The computer can be adapted for communication with an electronic network such as the Internet. One or more software applications are used to determine the identification information for the selected image characteristics. Software applications are also used to compare images, provide notification of identical images, and to generate a database of identified images.